.TH std::experimental::filesystem::is_socket 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::experimental::filesystem::is_socket \- std::experimental::filesystem::is_socket

.SH Synopsis
   Defined in header <experimental/filesystem>
   bool is_socket( file_status s );                 \fB(1)\fP (filesystem TS)
   bool is_socket( const path& p );                 \fB(2)\fP (filesystem TS)
   bool is_socket( const path& p, error_code& ec );

   Checks if the given file status or path corresponds to a named IPC socket, as if
   determined by the POSIX S_IFSOCK.

   1) Equivalent to s.type() == file_type::socket.
   2) Equivalent to is_socket(status(p)) or is_socket(status(p, ec)).

.SH Parameters

   s  - file status to check
   p  - path to examine
   ec - out-parameter for error reporting in the non-throwing overload

.SH Return value

   true if the file indicated by p or if the type indicated s refers to a named socket.
   The non-throwing overload returns false if an error occurs.

.SH Exceptions

   1)
   noexcept specification:
   noexcept

   2) The overload that does not take an error_code& parameter throws filesystem_error
   on underlying OS API errors, constructed with p as the first argument and the OS
   error code as the error code argument. std::bad_alloc may be thrown if memory
   allocation fails. The overload taking an error_code& parameter sets it to the OS API
   error code if an OS API call fails, and executes ec.clear() if no errors occur. This
   overload has
   noexcept specification:
   noexcept


.SH Notes

   Named sockets are UNIX domain sockets constructed with socket and bind POSIX APIs,
   which may be used for advanced interprocess communication. In particular, they may
   be used to transport open file descriptors from one running process to another.

   The information provided by this function is usually also provided as a byproduct of
   directory iteration. During directory iteration, calling is_socket(*iterator) is
   less efficient than is_socket(iterator->status()).

.SH Example


// Run this code

 #include <cstdio>
 #include <cstring>
 #include <experimental/filesystem>
 #include <fstream>
 #include <iostream>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/un.h>
 #include <unistd.h>

 namespace fs = std::experimental::filesystem;

 void demo_status(const fs::path& p, fs::file_status s)
 {
     std::cout << p;
     // alternative: switch(s.type()) { case fs::file_type::regular: ... }
     if (fs::is_regular_file(s))
         std::cout << " is a regular file\\n";
     if (fs::is_directory(s))
         std::cout << " is a directory\\n";
     if (fs::is_block_file(s))
         std::cout << " is a block device\\n";
     if (fs::is_character_file(s))
         std::cout << " is a character device\\n";
     if (fs::is_fifo(s))
         std::cout << " is a named IPC pipe\\n";
     if (fs::is_socket(s))
         std::cout << " is a named IPC socket\\n";
     if (fs::is_symlink(s))
         std::cout << " is a symlink\\n";
     if (!fs::exists(s))
         std::cout << " does not exist\\n";
 }

 int main()
 {
     // create files of different kinds
     fs::create_directory("sandbox");
     std::ofstream("sandbox/file"); // create regular file
     fs::create_directory("sandbox/dir");
     mkfifo("sandbox/pipe", 0644);
     struct sockaddr_un addr;
     addr.sun_family = AF_UNIX;
     std::strcpy(addr.sun_path, "sandbox/sock");
     int fd = socket(PF_UNIX, SOCK_STREAM, 0);
     bind(fd, (struct sockaddr*)&addr, sizeof addr);
     fs::create_symlink("file", "sandbox/symlink");

     // demo different status accessors
     for (auto it = fs::directory_iterator("sandbox"); it != fs::directory_iterator(); ++it)
         demo_status(*it, it->symlink_status()); // use cached status from directory entry
     demo_status("dev/null", fs::status("/dev/null")); // direct calls to status
     demo_status("dev/sda", fs::status("/dev/sda"));
     demo_status("sandbox/no", fs::status("/sandbox/no"));

     // cleanup
     close(fd);
     fs::remove_all("sandbox");
 }

.SH Possible output:

 "sandbox/file" is a regular file
 "sandbox/dir" is a directory
 "sandbox/pipe" is a named IPC pipe
 "sandbox/sock" is a named IPC socket
 "sandbox/symlink" is a symlink
 "dev/null" is a character device
 "dev/sda" is a block device
 "sandbox/no" does not exist

.SH See also

   status            determines file attributes
   symlink_status    determines file attributes, checking the symlink target
                     \fI(function)\fP
   file_status       represents file type and permissions
                     \fI(class)\fP
   status_known      checks whether file status is known
                     \fI(function)\fP
   is_block_file     checks whether the given path refers to block device
                     \fI(function)\fP
   is_character_file checks whether the given path refers to a character device
                     \fI(function)\fP
   is_directory      checks whether the given path refers to a directory
                     \fI(function)\fP
   is_fifo           checks whether the given path refers to a named pipe
                     \fI(function)\fP
   is_other          checks whether the argument refers to an other file
                     \fI(function)\fP
   is_regular_file   checks whether the argument refers to a regular file
                     \fI(function)\fP
   is_symlink        checks whether the argument refers to a symbolic link
                     \fI(function)\fP
   exists            checks whether path refers to existing file system object
                     \fI(function)\fP
                     cached status of the file designated by this directory entry
   status            cached symlink_status of the file designated by this directory
   symlink_status    entry
                     \fI\fI(public member\fP function of\fP
                     std::experimental::filesystem::directory_entry)

.SH Categories:
     * Noindexed pages
     * unconditionally noexcept
.SH Hidden categories:
     * Pages with unreviewed unconditional noexcept template
     * Pages with unreviewed noexcept template
